A composite structure is fabricated on tooling. Generally, the tooling is made as one piece. Thus, the tooling, form, or mold, is fabricated, and then the composite structure is fabricated on top of the tooling. Tooling is typically one sided, but could be two sided.
Typically, to form a composite structure, the composite material is placed on the tooling, and then pressure/vacuum is applied to hold the composite material during curing of the composite material, i.e. epoxy, thermoset composite, thermoplastic composite etc. Thus, to make a composite structure, the tooling is fabricated first, and then the composite structure. This process can be costly, especially for prototyping where one or two parts is made. What is needed is reconfigurable tooling, that can be easily and precisely configured and reconfigured to suit a particular need.
In one prior approach, reconfigurable modular tooling is proposed in U.S. Pat. No. 5,851,563 by Hoffman, herein incorporated by reference. A bed of pins is supported by a housing. Each pin is connected to a screw drive that allows the height of the entire array to be adjusted by a single motor that rasters across the unit. The work surface is defined by an array of “spring” heads which are mounted on ball joints and provide some degree of flexibility. A solid surface may be laid across these pins. In another approach, reconfigurable tooling is proposed for forming honeycomb cores in U.S. Pat. No. 6,209,380, by Papazian et al., herein incorporated by reference. In this approach, an array of rectangular cross section pins define a three dimensional work surface. The heads of the pins can be made of various types of spring loaded devises. This approach exhibits a degree pixelation of a surface, and thus is used for forming honeycomb cores, rather than the composite panels themselves.
What is needed is reconfigurable tooling that can provide a high stiffness continuous tool surface and still provide a large envelope of potential tool shapes. A continuous tool surface provides a high quality part exterior surface and also allows vacuum processing tools to be used reducing need for additional finish machining and lowering fabrication costs. Moreover, what is needed is a way to better tailor the surface shape of reconfigurable tooling than is possible with conventional tooling. Furthermore, what is needed is a way to control the local stiffness of a reconfigurable tooling surface.